Miele's box that they sell is 8.5 oz. I was told to run in it on the Sanitize cycle every one or two months depending on usage. When the Miele tech used it, he simply emptied the entire contents into the tub and ran the Sanitize cycle with no clothing.

Not sure if it's any much different on a 40 versus 42 , but the sanitize cycle does a 10 minute prewash and then dumps it out before it then does a long cycle.

When I do that, I usually put it in the dispenser, as all that product goes out on initial pre-rinse on sanitize on my 4840 if I dump it into the tub .

I also have the W 4840. Good point on the prewash.

How do I start a new thread? I want to know if citric acid will remove bleach odor in clothes, and how much to use?